4 FM quick reads on HVAC1. Geothermal heat pump systems

Geothermal systems have garnered new attention because of the growing interest in green design. Geothermal systems work by transferring heat to and from the ground or ground water. In cold weather, the liquid in the pipes draws heat from the subsurface; in warm weather, heat from the building is transferred into the ground.

In the most common design, closed loops of pipes are placed into the ground. In vertical systems, wells are dug up to 300 feet deep for the pipes. In horizontal systems, the pipes are laid in trenches 6 to 10 feet underground and are usually used for smaller buildings.

The environmental benefit is simple: Geothermal systems provide heating and cooling without the use of fossil fuels. What’s more, they use technology that is simple, reliable and efficient, with operating costs up to 60 percent less than conventional systems. But they are significantly more expensive to install. Paybacks range from 5 to 12 years.

The Right Way to Evaluate HVAC Payback

I’m Ed Sullivan, editor of Building Operating Management magazine. Today’s topic is ensuring that the CFO understands how to evaluate the payback from an HVAC upgrade.

The bottom-line impact of an HVAC retrofit isn’t always as easy to see as that of a lighting retrofit. Unless the use of a space changes, the demand for lighting will be the same after the upgrade as before. Not so with HVAC. Both heating and cooling load can vary dramatically from year to year.

Suppose the first year after the upgrade brings a hot summer or cold winter. If the reduction in energy costs is less than expected, the CFO may conclude that the upgrade was a failure.

A better course is to let the CFO know – when the project is first proposed – that the appropriate measure isn’t absolute dollars, but dollars adjusted for degree days. That’s not quite as simple an idea to sell to the CFO, but it’s hardly a difficult concept for anyone who pays home heating and cooling bills. More important, that approach helps prevent surprises when energy bills arrive.

Efficient HVAC Systems May Qualify for Tax Breaks

The Energy Policy Act of 2005 – better known as EPAct – provides tax deductions for the installation of HVAC systems with energy costs that are at least 16.7 percent than an HVAC system designed to meet the 2001 edition of ASHRAE 90.1. The deductions apply both to new construction and to renovations. Although HVAC component upgrades typically don’t qualify, a comprehensive system installation is a good candidate. So are geothermal and thermal storage systems.

Getting the deduction isn’t easy. EPAct requires that the performance of the system be substantiated by energy modeling. And the modeling required is different than the modeling required by LEED. But rebates may be available to cover at least some of the cost of modeling, though the rebates must be obtained before the modeling is conducted.

The tax benefits are currently due to expire at the end of 2008. But there are proposals in Congress to extend the tax breaks. For green buildings and other buildings where significant HVAC work is planned, the tax breaks are worth looking into.

Geothermal Systems Offer Efficient Heating and Cooling

Geothermal systems have garnered new attention because of the growing interest in green design. Geothermal systems work by transferring heat to and from the ground or ground water. In cold weather, the liquid in the pipes draws heat from the subsurface; in warm weather, heat from the building is transferred into the ground.

In the most common design, closed loops of pipes are placed into the ground. In vertical systems, wells are dug 300 or more feet deep for the pipes. In horizontal systems, the pipes are laid in trenches 6 to 10 feet underground and are usually used for smaller buildings.

The environmental benefit is simple: Geothermal systems provide heating and cooling without the use of fossil fuels. What’s more, they use technology that is simple, reliable and efficient, with operating costs up to 60 percent less than conventional systems. But they are significantly more expensive to install. Paybacks range from 5 to 12 years. The systems may qualify for tax deductions under the federal Energy Policy Act of 2005. Geothermal systems are good candidates for those tax benefits.